Fighting large fires, particularly in environments where fires can spread rapidly, requires use of high volume water or foam solution application rates and densities.
In-line balanced pressure proportioning modules are well known in the art. These in-line balanced pressure proportioning modules are located at a point in the fire suppression system to accurately supply proportioned foam solution. The principle of operation is based on the use of two orifices: one for the water supply and one for the foam concentrate supply, with both orifices discharging into a common reduced pressure area. The water is supplied by a water pump at the required pressure, and the foam liquid is supplied from another pump or other pressure source. These proportioners automatically balance the foam liquid pressure and water pressure to provide correct proportioning, even though the water pressure may vary at points in the system. In-line balanced pressure proportioning modules are available on the market from such manufacturers as National Foam, 150 Gordon Drive, Lionville, Pa. 19353.
Fighting large industrial fires, such as those involving storage tanks in petroleum refineries and petrochemical complexes, often requires foam solution discharges in the range of 5000 gallons per minute (GPM). Currently, foam solution discharge rates in this range require the use of four to five industrial foam pumpers at a cost of $175,000 to $200,000 each. Using state-of the-art equipment available on the market today, fighting a single fire can easily require a capital investment of up to $1,000,000.
Accordingly, conventional fighting of these large scale fires requires significant capital expenditures. Once the fire spreads, the possibility for ordering additional fire fighting equipment arises; the consequent delay hampers efficiency. It has therefore become desirable to devise an economical way of fighting large scale fires in an efficient and effective manner.